This invention relates to a method of producing carbon nanotubes and to a device therefor,
Carbon nanotubes are recently discovered, hollow graphite tubules having a diameter of generally several to several tens nanometers. One method for the preparation of carbon nanotubes is disclosed in Nature, 358, 220 (1992) by Ebbesen et al. In this method, a DC potential of about 18 V is applied between a 6 mm diameter graphite rod (anode) and a 9 mm diameter graphite rod (cathode) which are coaxially disposed in a reaction vessel maintained in an inert gas atmosphere. By positioning the two rods close to each other, an arc discharge occurs with the simultaneous deposition of a carbonaceous material containing carbon nanotubes on the cathode rod. Since the anode rod is consumed as the arc discharge proceeds, the anode (or cathode) is occasionally displaced to maintain a constant gap.
The known method has a problem because it is not possible to continuously produce carbon nanotubes in a large amount. Further, since carbonaceous deposits are gradually accumulated on the cathode, it is difficult to maintain the optimum gap between the anode and the cathode and, thus, to maintain the optimum conditions for the production of carbon nanotubes.